Description of this paper

An initial amount of a radioactive substance y0?is given, along with information about the amount remaining after a given time t in appropriate units. For an equation of the form y = y0ekt?that models the situation, give the exact value of k in terms of natural logarithms: y0?= 2.56 lb; After 2 yr, 0.64 lb remains.

y o=2.56 l b

y=0.64 lb

t=2 yrs

The general decay equation is:

y= y o e

kt

Since the quantity of substance decreases with time, the equation should be rewritten as: